JP2012108063A - Rotation angle detection apparatus and steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enlarge a degree of freedom in designing a rotary component group composed of a main rotary component and sub rotary components which are linked with each other for detecting a rotation angle of a rotary component in a rotation angle detection apparatus.SOLUTION: A rotation angle detection apparatus 4 includes a main rotary component 41 which is rotated integrally with an output shaft 21 of a steering device 1 around a rotation centerline L, first and second sub rotary components 51 and 61 which are rotated while being linked with the main rotary component 41 in a predetermined rotation ratio, first and second magneto-resistance elements 71 and 72 which output first and second detection signals S1 and S2 corresponding to first and second rotation angles θ1 and θ2 of the first and second sub rotary components 51 and 61, and rotation angle detection means 49 which detects a steering angle θ on the basis of the first and second detection signals S1 and S2. Between the main rotary component 41 and the first/second sub rotary component 51/61, rotations are transferred by friction between contact faces 42 and 52/42 and 62 of the main rotary component 41 and the first/second sub rotary component 51/61.

Description

  The present invention relates to a rotation angle detection device and a steering device that detect a rotation angle of a rotation member. The rotation angle detection device detects a steering angle that is a rotation angle in the steering device.

  As a rotation angle detection device that detects a rotation angle (for example, a steering angle) of a rotation member (for example, a rotation shaft that is rotationally driven by an operation of a steering wheel in a vehicle steering device), a gear ( Hereinafter referred to as “main gear”), first and second gears interlocking with the main gear, and first and second rotation angles for outputting detection signals according to the rotation angles of the first and second gears. What is provided with a sensor is known (for example, refer patent document 1).

Japanese National Patent Publication No. 11-500828

As in the case of the rotation angle detection device, when the rotating parts that are linked to each other in order to detect the rotation angle of the rotation member are composed of gears (the main gear and the first and second gears), the number of teeth is an integer. And the gear module is determined from the viewpoint of the strength of the teeth, so when the rotation ratio between the main gear and the first and second gears is set, the main gear and the first and first gears are set. Each outer diameter (tooth tip circle diameter) of the second gear is determined. For this reason, the arrangement and combination of the main gear and the first and second gears, and the overall size of the rotating component group composed of the main gear and the first and second gears are limited by the number of teeth and the module. Therefore, the degree of freedom in designing the rotating component group is reduced. As a result, for example, it becomes difficult to arrange the rotating component group in a desired space, and the degree of freedom in arranging the rotating component group becomes small. In addition, downsizing of the rotating parts group is limited.
This is because the rotation transmission part of the rotating part (when the rotating part is a gear, the tooth part of the gear corresponds to this, hereinafter referred to as “rotation transmission part”) is linked with another rotating part. And a rotation transmission element having a predetermined width in the circumferential direction or the rotation direction (when the rotating component is a gear, the teeth of the gear correspond to each other, hereinafter referred to as “rotation transmission element”). Is unique.

The present invention has been made in view of such circumstances, and in the rotation angle detection device, a rotation component group composed of a main rotation component and a sub rotation component that are interlocked with each other to detect the rotation angle of the rotation component. The purpose is to increase the degree of design freedom.
The present invention further aims to improve the detection accuracy of the rotation angle of the rotating component by devising the shape of the contact surface of the main rotating component and the sub rotating component, and the sensor housing of the steering device. An object of the present invention is to enable accommodation of a rotation angle detection device in a sensor housing without increasing the size of the sensor housing.

  The invention according to claim 1 includes a main rotating component (41) provided on the rotating member (21) and rotating integrally with the rotating member (21) about the rotation center line (L), and the main rotating component ( 41) with respect to the rotation angle (θ1, θ2) of the sub rotation component (51, 61) rotating in conjunction with the main rotation component (41) at a predetermined rotation ratio and the sub rotation component (51, 61). Rotation angle sensors (71, 72) for outputting corresponding detection signals (S1, S2), and rotation angles for detecting the rotation angle (θ) of the rotation member (21) based on the detection signals (S1, S2). In the rotation angle detection device (4) provided with the detection means (49), the transmission of rotation between the main rotating component (41) and the sub rotating component (51, 61) is transmitted to the main rotating component (41). ) And the contact surface (42, 2; 42, 62) is a rotation angle detection device is performed by friction between (4).

  According to this, in the rotation angle detection device that detects the rotation angle of the rotation member based on the detection signal corresponding to the rotation angle of the sub rotation component that rotates in conjunction with the main rotation component that rotates integrally with the rotation member, Transmission of rotation between the rotating component and the sub-rotating component is performed by friction between the contact surface of the main rotating component and the contact surface of the sub-rotating component that are in contact with each other. For this reason, in a state where a predetermined rotation ratio is set, the degree of freedom in setting the outer diameter of each rotation transmission portion constituted by the contact surfaces of the main rotating component and the sub rotating component, and therefore from the main rotating component and the sub rotating component. When there is a restriction that the degree of freedom of design of the rotating component group to be configured is an integral multiple of a rotation transmitting element having a predetermined width in the circumferential direction or the rotating direction (for example, the main rotating component and the sub rotating component are configured by gears) Can be made larger than As a result, the degree of freedom of arrangement of the rotating component group is increased, and the rotating component group can be easily downsized.

According to a second aspect of the present invention, in the rotation angle detecting device (4) according to the first aspect, the auxiliary rotating parts (51, 61) include a first auxiliary rotating part (51) and the first auxiliary rotating part. A second sub-rotation component (61) having the contact surface (62) having an outer diameter different from the outer diameter of the contact surface (52) of (51), and the rotation of the sub-rotation component (51, 61). The angles (θ1, θ2) are a first rotation angle (θ1) of the first sub-rotating component (51) and a second rotation angle (θ2) of the second sub-rotating component (61), and the rotation The angle sensor (71, 72) includes a first rotation angle sensor (71) that outputs a first detection signal (S1) that is the detection signal (S1, S2) according to the first rotation angle (θ1); A second detection signal (S2) that is the detection signal (S2) corresponding to the second rotation angle (θ2) is output. Those at a rotation angle sensor (72).
According to this, even when the sub-rotation component is composed of at least two sub-rotation components having different outer diameters of the contact surfaces, rotation transmission between the main rotation component and each sub-rotation component is performed by friction. As a result, the degree of freedom of arrangement of the sub-rotating parts with respect to the rotating member and the main rotating parts increases. Furthermore, the degree of freedom in setting the outer diameter of the contact surface of each sub-rotating component is greater than when the first and second sub-rotating components are configured with gears, and the size of the rotating component group can be easily reduced. become.

According to a third aspect of the present invention, in the rotation angle detecting device (4) according to the first or second aspect, the contact surface (42, 52, 62) is a tapered surface (F).
According to this, since the contact surface is a tapered surface, the area of the contact surface can be increased, so it is easy to ensure the frictional force to prevent slippage between the contact surfaces that are in contact with each other. Further, the contact pressure can be reduced. As a result, slippage between the contact surfaces is prevented, so that the detection accuracy of the rotation angle is improved. Further, the occurrence of wear on the contact surface can be suppressed, and the period during which the rotation angle of the rotating component can be detected with good accuracy can be extended.

According to a fourth aspect of the present invention, in the rotation angle detecting device (4) according to the third aspect, a longitudinal section of each contact surface (42, 52, 62) in a plane including the rotation center line (L). The shape is a V-shaped convex shape or a V-shaped concave shape formed by the pair of tapered surfaces (F1, F2).
According to this, since the contact surface of the V-shaped convex shape and the contact surface of the V-shaped concave shape are in contact with each other, the relative positional deviation in the axial direction between the main rotating component and the sub-rotating component is changed. It can be prevented only by mutual contact. As a result, a dedicated member for preventing the displacement is not required, the structure of the rotation angle detection device can be simplified, and the rotation angle detection device can be miniaturized.
Further, by reducing the angle formed by the pair of tapered surfaces, the wedge effect can be exhibited, and the wedge effect that increases the force acting on the tapered surface in a direction perpendicular to each tapered surface can be exhibited. Since it can do, the frictional force which acts between contact surfaces becomes large. As a result, the effect of preventing the occurrence of slippage between the contact surfaces is improved, and the detection accuracy of the rotation angle of the sub-rotating component and the rotating member is improved.

According to a fifth aspect of the present invention, in the rotation angle detection device (4) according to any one of the first to fourth aspects, the contact portion (T1; T2) between the contact surfaces (42, 52; 42, 62). ), Pressing members (45, 55, 65) for pressing the contact surfaces (42, 52; 42, 62) with each other are provided.
According to this, since the contact surfaces press each other at the contact portion by the pressing member, the frictional force between the contact surfaces increases accordingly. As a result, the effect of preventing the occurrence of slippage between the contact surfaces is improved, and the detection accuracy of the rotation angle of the sub-rotating component and the rotating member is improved.

The invention according to claim 6 is the rotation angle detection device (4) according to any one of claims 1 to 5, a torque detection device (5) for detecting a steering torque by the steering operation member (10), In the steering device (1) including the sensor housing (13), the rotation angle (θ) of the rotation member (21) is a steering angle (θ) based on an operation of the steering operation member (10), The rotation angle detection device (4) is housed in the sensor housing together with the torque detection device (5).
According to this, in the rotation angle detection device, the degree of freedom of setting the outer diameter of each contact surface of the main rotating component and the sub rotating component is increased, so that the arrangement of the sub rotating component with respect to the rotating member and the main rotating component can be improved. Since the degree of freedom is large and the degree of freedom of arrangement of the rotating parts group is large, in a steering device including a sensor housing in which a torque detection device is accommodated, the rotation angle is detected in the sensor housing without increasing the size of the sensor housing. The device can be accommodated.

According to the rotation angle detection device of the present invention, it is possible to increase the degree of freedom in designing a rotating component group composed of a main rotating component and a sub rotating component that are linked to each other in order to detect the rotating angle of the rotating component.
According to the rotation angle detection device of the present invention, the detection accuracy of the rotation angle of the rotating component can be improved by devising the shapes of the contact surfaces of the main rotating component and the sub rotating component.
According to the steering device of the present invention, the rotation angle detection device can be accommodated in the sensor housing without increasing the size of the sensor housing of the steering device.

FIG. 3 is a longitudinal sectional view of a main part of a steering apparatus including a rotation angle detection device according to the embodiment of the present invention, and is a sectional view taken along line II in FIG. 2. It is a schematic diagram in the II-II line cross section of FIG. It is a perspective view of the magnet with which the rotation angle detection apparatus of FIG. 1 is provided. It is a graph explaining the detection signal and steering angle which are detected by the rotation angle detection apparatus of FIG. FIG. 7 is a schematic diagram of a main part longitudinal section of the rotation angle detection device of FIG. 1, showing a modification of the embodiment of FIG. 1. It is a figure which shows another modification of embodiment of FIG. 1, and is equivalent to FIG. It is a figure which shows another modification of embodiment of FIG. 1, and is equivalent to FIG.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
Referring to FIG. 1, a steering device 1 as a machine including a rotation angle detection device 4 is mounted on an automobile as a vehicle and steers the steered wheels.
In addition to the rotation angle detection device 4 that detects the steering angle θ (see FIG. 4), the steering device 1 includes a rotation mechanism 2 that includes a steering wheel 10 that rotates by a steering force as an operation force applied by the driver, and a rotation mechanism. 2 and a transmission mechanism (not shown) for transmitting the force output from the gear box 3 to a steered wheel (not shown). ), A torque detection device 5 that detects a steering torque that is a torque based on the steering force, and an auxiliary force generation having an electric motor 31 as an actuator that generates an auxiliary force that reduces the steering force applied to the steering wheel 10 by the driver. This is an electric power steering device including the device 6 and a control device 7 that controls the operation of the electric motor 31.
The steering angle θ detected by the rotation angle detection device 4 is used for various types of vehicle control (for example, four-wheel steering, suspension device or brake device control).

  In addition to the steering wheel 10 that is a steering operation member as an operation member, the rotation mechanism 2 is a rotation connection that connects the steering shaft 11 as a rotation shaft connected to the steering wheel 10 and the steering shaft 11 and the input shaft 20. Member 12. The rotation of the steering wheel 10 is transmitted to the output shaft 21 through the steering shaft 11, the rotary connecting member 12, and the input shaft 20 that rotate together with the steering wheel 10. At this time, the rotation transmission system from the steering wheel 10 to the output shaft 21 rotates so as to have a one-to-one rotation angle relationship.

  The gear box 3 includes a housing 13 attached to the vehicle body, an input shaft 20 as a rotating shaft to which a steering force from the steering wheel 10 is transmitted, and an output shaft 21 as a rotating shaft to which the rotation of the input shaft 20 is transmitted. The torsion bar 22 as a rotation shaft for connecting the input shaft 20 and the output shaft 21 so as to be relatively rotatable, and the steering wheel based on the rotation of the input shaft 20 transmitted through the torsion bar 22 and the output shaft 21 sequentially. A rack and pinion mechanism 23 is provided as a drive mechanism that outputs a driving force for steering to the transmission mechanism.

The housing 13 that houses the input shaft 20, the output shaft 21, the torsion bar 22, and the rack and pinion mechanism 23 includes a first housing 14 that rotatably supports the input shaft 20, and a rack that supports the output shaft 21 rotatably. A second housing 15 that accommodates the pinion mechanism 23 is included.
The first housing 14 and the second housing 15 having a mounting portion to the vehicle body of the automobile are integrated by being coupled to each other by bolts 16 as coupling means at the ends in the axial direction.

  Here, the axial direction is assumed to be a direction parallel to the rotation center line L of the output shaft 21 which is a rotating member. Further, it is assumed that the radial direction and the circumferential direction are a radial direction and a circumferential direction around the rotation center line L, respectively. In the embodiment, for convenience, as shown in FIG. 1, the vertical direction is a direction parallel to the axial direction, and one direction in the axial direction and one of the other directions are the upward direction, and the axial direction It is assumed that the other of the one direction and the other direction is the downward direction.

The steering wheel 10, the steering shaft 11 and the rotation connecting member 12, and the input shaft 20, the torsion bar 22 and the output shaft 21, which are constituent members of the rotation mechanism 2, are all rotation members. Further, the rotation center line L of the output shaft 21 coincides with the rotation center line of the input shaft 20.
The rack and pinion mechanism 23 includes a pinion 24 provided on the output shaft 21 and a rack shaft 25 provided with a rack 26 that meshes with the pinion 24. The rack shaft 25 that is driven by the pinion 24 and reciprocates in the left-right direction of the automobile steers the steered wheels via the tie rods that the transmission mechanism has.

  A torque detection device 5 that detects a steering torque based on the amount of torsion of the torsion bar 22 is a well-known one. For example, as disclosed in Japanese Patent Application Laid-Open No. 2007-93380, the input shaft 20 and the output shaft 21 are connected to each other. Each of the first housing 14 is provided with an input side core 27 and an output side core 28 made of magnetic materials facing each other with a gap in the axial direction and with a gap in the circumferential direction, and surrounding the cores 27, 28. And an annular coil 29 attached thereto. The torsion bar 22 is twisted by the steering force applied to the steering wheel 10, and the circumferential positions of the input shaft side core 27 and the output shaft side core 28 change relatively. A steering torque is detected based on the generated voltage change in the coil 29.

  In the housing 13, the torque detection device 5 and the rotation angle detection mechanism 40 included in the rotation angle detection device 4 are arranged in series in the axial direction so that the torque detection device 5 is positioned above the rotation angle detection mechanism 40. Arranged side by side. Therefore, the housing 13 is also a sensor housing that houses the torque detection device 5 and the rotation angle detection mechanism 40. As another example, the torque detection device 5 may be disposed below the rotation angle detection mechanism 40.

The auxiliary force generation device 6 includes an electric motor 31 controlled by a control device 7 to which a steering torque is input, and a worm gear 32 as a transmission mechanism that transmits the torque of the electric motor 31 to the pinion 24. The worm gear 32 accommodated in the second housing 15 is fixed to the output shaft 21 by press fitting with the worm 33 that rotates integrally with the rotating shaft of the electric motor 31 attached to the second housing 15 and rotates integrally with the output shaft 21. And a worm wheel 34.
The control device 7 attached to the outer surface of the housing 13 is composed of a computer including a central processing unit and a storage device.

  In such a steering device 1, when a steering torque generated by a steering force applied by the driver to the steering wheel 10 is transmitted to the input shaft 20, the input shaft 20 is torsioned due to road resistance acting on the steering wheel. The output shaft 21 is rotated while twisting the bar 22, and the rack shaft 25 driven by the pinion 24 moves in the left-right direction (the axial direction of the rack shaft 25). At the same time, the control device 7 controls the electric motor 31 so as to generate an auxiliary force corresponding to the steering torque detected by the torque detection device 5 based on the twist of the torsion bar 22. Then, the auxiliary force by the electric motor 31 is transmitted to the rack shaft 25 via the worm gear 32, the output shaft 21 and the pinion 24, and the driver's steering force is reduced.

  Referring to FIGS. 1 and 2, a rotation angle detection device 4 that detects a steering angle θ that is an operation angle of the steering wheel 10 includes a rotation angle detection mechanism 40 having magnetoresistive elements 71 and 72, and a rotation angle detection mechanism 40. Rotation angle detecting means 49 for detecting the steering angle θ based on the detection signals S1, S2 from The steering angle θ is the rotation angle of the output shaft 21 in this embodiment. The steering direction can be detected by the torque detection device 5, the magnetoresistive elements 71 and 72, or other known means.

  The rotation angle detection mechanism 40 includes a main rotation component 41 that rotates around the same rotation center line as the rotation center line L, and first and second sub rotations that constitute a sub rotation component that rotates in conjunction with the main rotation component 41. The first and second detection signals as the detection signals according to the first and second rotation angles θ1 and θ2 (see FIG. 4) as the sub-rotation angles that are the rotation angles of the sub-rotation components 51 and 61. Detection by first and second magnetoresistive elements 71 and 72 as first and second rotation angle sensors constituting a rotation angle sensor that outputs detection signals S1 and S2, and detection by first and second magnetoresistive elements 71 and 72 And first and second magnets 81 and 82, which are magnets as magnetism generating members that are target portions. The main rotating component 41 and the sub rotating components 51 and 61 that are interlocked with each other constitute a rotating component group R.

The main rotating component 41 is provided so as to rotate integrally with the output shaft 21 with respect to the output shaft 21. Therefore, the main rotating component 41 is fixed to the output shaft 21 so as not to move in the axial direction and the circumferential direction.
As another example, the main rotating component 41 may be coupled to the output shaft 21 so as to be movable in the axial direction, for example, by serration coupling, and to be immovable or substantially immovable in the circumferential direction. At this time, a stopper is provided to restrict the movement of the main rotating component 41 in the axial direction.

  The first and second auxiliary rotating parts 51 and 61 are disposed radially outwardly with respect to the main rotating part 41 provided fixed to the output shaft 21 and spaced in the circumferential direction. The sub-rotating parts 51 and 61 are rotatably supported by a support plate 17 that is a support portion provided in the housing 13 via a bearing 90, and the rotation center lines L 1 and L 2 are the rotation centers of the main rotating part 41. It is parallel to the rotation center line L which is also a line.

  The bearing 90 is held by holders 91 and 92 that are provided on the support plate 17 so that the position in the radial direction is adjustable. For this reason, each of the sub-rotating parts 51 and 61 is supported by the holders 91 and 92, which are position-adjustable adjusting members, via the bearings 90. By moving in the radial direction toward the component 41, the pressing force pressing the sub-rotating components 51 and 61 radially inward against the main rotating component 41 (or the main rotating component 41 and each sub-rotating in the radial direction). It is possible to increase the pressing force that presses the components 51 and 61 against each other, and consequently increase the frictional force, so that the contact surface 42 of the main rotating component 41 and the contact surfaces of the sub rotating components 51 and 61 that are in contact with each other in the radial direction. The effect of preventing the occurrence of slipping between 52 and 62 is enhanced.

Transmission of rotation (or torque) between the main rotation component 41 and the first sub rotation component 51 and rotation (or torque) between the main rotation component 41 and the second sub rotation component 61 Transmission is the friction between the contact surfaces 42 and 52 of the main rotating component 41 and the first sub rotating component 51, and the contact surfaces 42 and 62 of the main rotating component 41 and the second sub rotating component 61, respectively. This is done by friction.
Each contact surface 42, 52, 62 is an outer peripheral surface of each rotating component 41, 51, 61 that is a disk-shaped member, and is a rotating surface having each rotation center line L, L1, L2 as a central axis. Furthermore, it is a rotation transmission part which transmits rotation between rotation components 41 and 51; 41,61.

  In each of the contact surfaces 42, 52, 62, a friction coefficient is large or friction is generated in order to prevent slippage between the contact surfaces 42, 52; 42, 62 that are in contact with each other at the contact portion T1; T2. Since it is preferable that the force is large, each of the contact surfaces 42, 52, and 62 is a friction surface having a high friction coefficient. Therefore, each contact surface 42, 52, 62 is formed of, for example, a rough surface, or the outer peripheral portion that is the portion having the contact surface 42, 52, 62 in each rotary component 41, 51, 61 is at least high. Formed of a material having a coefficient of friction (for example, a high friction material used in a brake device or a material having a coefficient of friction of 0.5 or more, hereinafter referred to as “high friction material”), or Formed by a film or layer of high friction material.

The outer diameters of the first and second auxiliary rotating parts 51 and 61 are smaller than the outer diameter of the main rotating part 41, and the outer diameter of the first auxiliary rotating part 51 is smaller than the outer diameter of the second auxiliary rotating part 61. Here, the outer diameter of each rotary component 41, 51, 61 is the outer diameter of each contact surface 42, 52, 62 in this embodiment. In each rotating component 41, 51, 61, the outer diameter of each contact surface 42, 52, 62 is a predetermined rotation that is a rotation ratio of each sub rotating component 41, 51, 61 with respect to the main rotating component 41, 51, 61. The outer diameter that determines the ratio. For example, when the rotation of the main rotating component 41 is A times, the first and second auxiliary rotating components 51 and 61 are set to outer diameters that rotate B times and C times, respectively.
Here, A, B, and C are different integers (natural numbers) or numbers other than integers, and A <B <C. The predetermined rotation ratio of the first rotation component 51 to the main rotation component 41 is B / A, and the predetermined rotation ratio of the second rotation component 61 to the main rotation component 41 is C / A.

  All or a part of each contact surface 42, 52, 62 is a tapered surface F having the rotation center line L as a central axis. The taper surface F has a first taper surface F1 that faces upward (one direction in the axial direction) as its normal line goes radially outward, and its normal line goes radially outward. When the second taper surface F2 is directed downward (the direction opposite to the one direction and the other direction in the axial direction) as it goes, the main rotating component 41 and the sub rotating components 51 and 61 are: When the contact surface 42 of the main rotating component 41 is one of the first tapered surface F1 and the second tapered surface F2, the contact surfaces 52, 62 of the auxiliary rotating components 51, 61 are the first tapered surface. The other tapered surface of the surface F1 and the second tapered surface F2 contacts each other.

In this embodiment, all or a part of each contact surface 42, 52, 62 is composed of a pair of tapered surfaces F1, F2 whose planes of symmetry are orthogonal to the rotation center line L. And the longitudinal cross-sectional shape of the contact surfaces 42, 52, 62 is a V-shaped convex shape or a V-shaped concave shape. The main rotating component 41 and the sub rotating components 51 and 61 are in contact with each other on the tapered surfaces F1 and F2 of the contact surfaces 42 and 52; Here, the vertical cross-sectional shape is a cross-sectional shape on a plane including the rotation center line L.
Therefore, the main rotating component 41 and each of the sub rotating components 51 and 61 are such that the contact surface 42 of the main rotating component 41 is a V-shaped one of a V-shaped convex shape and a V-shaped concave shape. When the surfaces are F1 and F2, the contact surfaces 52 and 62 of the sub-rotating parts 51 and 61 are tapered surfaces F2 and F1 that are the other V-shaped of the V-shaped convex shape and the V-shaped concave shape. , Contact each other.

  As shown in FIG. 3, each of the magnets 81 and 82 is composed of a cylindrical permanent magnet having a semi-cylindrical N pole and a semi-cylindrical S pole. As shown in FIGS. 1 and 2, the first and second magnets 81 and 82 that rotate integrally with the first and second sub-rotating components 51 and 61 have first and second rotation center lines. It is fixed to the first and second rotating parts 51 and 61 so as to coincide with the rotation center lines L1 and L2 of the two sub rotating parts 51 and 61, respectively.

  The first and second magnetoresistive elements 71 and 72 are fixed to the first housing 14 so as to be disposed opposite to the first and second magnets 81 and 82 in the axial direction. The magnetoresistive elements 71 and 72 that are magnetic detection elements exhibit different resistance values depending on the direction of the magnetic field formed by the corresponding magnets 81 and 82.

Referring to FIG. 1, the rotation angle detection means 49 processes the detection signals S1 and S2 output from the first and second magnetoresistive elements 71 and 72 to obtain a main rotation angle that is a rotation angle of the output shaft 21, That is, it is a calculation means for calculating the steering angle θ, and is provided in the control device 7.
As another example, the rotation angle detection means 49 may be configured by a part of a control device that includes a microprocessor and is disposed in the housing 13, separately from the control device 7. In this case, the entire rotation angle detection device 4 can be accommodated in the housing 13.

The steering angle θ is detected by the rotation angle detection means 49 as follows.
Referring to FIGS. 1 and 4, the electric resistance values of the magnetoresistive elements 71 and 72 change according to the direction of the magnetic field. The magnets 81 and 82 that rotate integrally cause a change in resistance value that changes in a sinusoidal shape with the rotation every half rotation (180 °) of each sub-rotation component 51 and 61 as one cycle. Therefore, the first and second detection signals S1 and S2 having a period of 180 ° are obtained corresponding to the voltage change by the magnetoresistive elements 71 and 72.

  The rotation angle detection means 49 makes it easy to calculate the rotation angle of the main rotating component 41 (ie, the steering angle θ), and each of the sine wave-like input from the first and second magnetoresistive elements 71 and 72. As shown in FIG. 4, the first and second detection signals S1 and S2 are sawtooth-shaped first and second, each of which rotates each rotation (360 °) of each of the sub-rotating components 51 and 61 as one cycle. Conversion into secondary detection signals S12 and S22.

  Then, the rotation angle detecting means 49 is linearly rotated by the A rotation of the output shaft 21 corresponding to the A rotation of the steering wheel 10 based on the first and second secondary detection signals S12 and S22. By converting the angle detection signal S, the steering angle θ is detected. FIG. 4 shows an example in which the rotations A, B, and C are integers.

This rotation angle detection signal S is, for example, a first integrated value S13 of the first secondary detection signal S12 from the origin of the main rotation angle (indicated by “0” in FIG. 4) By subtracting the second integrated value S23 (partially indicated by a thin two-dot chain line in FIG. 4) of the second secondary detection signal S22 from the part indicated by the chain line), the output shaft 21 It is obtained as a signal proportional to the rotation, that is, the rotation of the steering wheel 10. Here, the first and second integrated values S12 and S23 correspond to the first and second rotation angles θ1 and θ2, respectively.
Since the rotation angle detection signal S corresponding to the steering angle θ is calculated by subtraction of the first and second secondary detection signals S12 and S22, the first and second of the magnetoresistive elements 71 and 72 are calculated. Since the influence of temperature on the detection signals S1 and S2 can be offset, the detection accuracy of the steering angle θ can be increased.
In the steering device 1, as shown in FIG. 4, the rotation angle of 720 ° as the central position in the rotation angle range of the steering angle θ (main rotation angle) corresponds to the neutral position of the steering wheel 10. The reference rotation angle is set.

Next, operations and effects of the embodiment configured as described above will be described.
The rotation angle detection device 4 is provided on the output shaft 21 that is the rotation shaft of the steering device 1 and rotates together with the output shaft 21 around the rotation center line L, and the main rotation component at a predetermined rotation ratio. First and second sub-rotating parts 51 and 61 that rotate in conjunction with 41, and first and second rotation angles θ1 and θ2 corresponding to the first and second rotation angles θ1 and θ2 of the first and second sub-rotating parts 51 and 61, respectively. First and second magnetoresistive elements 71 and 72 that output detection signals S1 and S2, and rotation angle detection means 49 that detects a steering angle θ based on the first and second detection signals S1 and S2, respectively. Transmission of rotation between the rotating component 41 and the first and second auxiliary rotating components 51, 61 is performed by contacting the contact surfaces 42, 52; 42, 42 of the main rotating component 41 and the first and second auxiliary rotating components 51, 61. It is performed by friction between 62.

  With this structure, the transmission of rotation between the main rotating component 41 and the first and second auxiliary rotating components 51 and 61 causes the contact surface 42 of the main rotating component 41 and the first and second auxiliary rotating components 51 and 61 to contact each other. This is done by friction between the contact surfaces 52 and 62. Therefore, each contact between the main rotating component 41 and the first and second sub rotating components 51 and 61 in a state where a predetermined rotation ratio between the main rotating component 41 and the first and second sub rotating components 51 and 61 is set. The degree of freedom in setting the outer diameter of the surfaces 42, 52, 62 (that is, each rotation transmission portion), and thus the degree of freedom in designing the rotating component group R composed of the main rotating component 41 and the sub rotating components 51, 61, When there is a restriction that is an integral multiple of a rotation transmission element having a predetermined width in the circumferential direction or the rotation direction (assuming that the main rotating component 41 and the first and second auxiliary rotating components 51 and 61 are constituted by gears) In comparison, it can be enlarged. As a result, the degree of freedom of arrangement of the rotating component group R is increased, and the rotating component group R can be easily downsized.

  Further, when the sub-rotation component is composed of at least two first and second sub-rotation components 51 and 61 having different outer diameters of the contact surfaces 52 and 62, the main rotation component 41 and each sub-rotation component 51, 61 Since the transmission of rotation between 61 is performed by friction, the degree of freedom of arrangement of the first and second auxiliary rotating parts 51 and 61 with respect to the output shaft 21 and the main rotating part 41 is increased. Furthermore, the degree of freedom in setting the outer diameters of the contact surfaces 52 and 62 of the sub-rotating components 51 and 61 is greater than when the first and second sub-rotating components 51 and 61 are configured with gears. Thus, the rotating component group R can be easily downsized.

  The contact surfaces 42, 52, 62 of the rotary components 41, 51, 61 are tapered surfaces F having the rotation center line L as the central axis, so that the contact surfaces 42 in the axial direction parallel to the rotation center line L are obtained. , 52, 62 by reducing the width of the rotary parts 41, 51, 61 in the axial direction by reducing the width of the contact surfaces 42, 52, 62. It is easy to secure a frictional force for preventing slippage between the contact surfaces 42, 52; 42, 62, and the contact pressure can be reduced. As a result, since the slip between the contact surfaces 42, 52; 42, 62 is prevented, the detection accuracy of the steering angle θ is improved. Further, the occurrence of wear on the contact surfaces 42, 52, 62 can be suppressed, and the period during which the first and second rotation angles θ1, θ2 and the steering angle θ can be detected with good accuracy can be extended.

  Each contact surface 42, 52, 62 has a V-shaped convex shape or a V-shaped concave shape formed by a pair of tapered surfaces F1, F2 in a cross section in a plane including the rotation center line L. It is. With this structure, the V-shaped convex contact surfaces 52 and 62 and the V-shaped concave contact surface 42 come into contact with each other, so that the relative relationship in the axial direction between the main rotating component 41 and the sub-rotating components 51 and 61 is established. Can be prevented only by contact between the contact surfaces 42, 52; As a result, a dedicated member for preventing the displacement is not required, the structure of the rotation angle detection device 4 can be simplified, and the rotation angle detection device 4 can be reduced in size.

  In the rotation angle detection device 4, the degree of freedom of arrangement of the first and second sub-rotation parts 51 and 61 relative to the output shaft 21 and the main rotation part 41 is large, and the degree of freedom of arrangement of the rotation part group R is large. In the steering device 1 including the housing 13 in which the torque detection device 5 is accommodated, the rotation angle detection device 4 can be accommodated in the housing 13 without increasing the size of the housing 13.

  Hereinafter, with reference to FIGS. 5 to 7, an embodiment in which a part of the configuration of the embodiment is changed will be described with respect to the changed configuration. In addition, the same code | symbol is used as needed about the same member etc. as the member of the said embodiment, or a corresponding member.

Referring to FIGS. 5 and 6, the main rotating component 41 and the auxiliary rotating components 51 and 61 are in contact with each other at the contact surfaces 42 and 52; 42 and 62 each having a single tapered surface F 1 or a tapered surface F 2.
More specifically, referring to FIG. 5, each rotation center line L1, L2 is parallel to the rotation center line L, and the contact surface 42 of the main rotating component 41 is the first tapered surface F1 and the second tapered surface. When it is one of the tapered surfaces of F2, the contact surfaces 52 and 62 of the sub-rotating parts 51 and 61 are in contact with each other at the other tapered surface of the first tapered surface F1 and the second tapered surface F2. . FIG. 5 shows an example in which the contact surface 42 of the main rotating component 41 is the second tapered surface F2, and the contact surfaces 52 and 62 of the auxiliary rotating components 51 and 61 are the first tapered surface F1. Yes.

Referring to FIG. 6, each of the rotation center lines L1 and L2 is a plane that includes the rotation center line L and is on a different plane or the same plane and intersects the rotation center line L. The contact surface 42 of the main rotating component 41 is the outer peripheral surface 48b of the main rotating component 41 and the first tapered surface F1 or the second tapered surface F2, and the contact surfaces 52, Reference numeral 62 denotes a tapered surface F having the rotation center lines L1 and L2 as center axis lines. FIG. 6 shows an example in which the contact surface 42 of the main rotating component 41 is the first tapered surface F1.
Here, the holder for holding the bearing 90 is capable of adjusting the position in the axial direction so that the pressing force pressing the main rotating component 41 and the sub rotating components 51 and 61 against each other acts in the axial direction. ) Is provided by being attached to a support portion (not shown).
In the modification shown in FIG. 6, the contact surface 42 is formed on the end surface (upper end surface 48 b or lower end surface 48 c) in the radial direction inner side than the outer peripheral surface 48 b of the main rotating component 41 and in the axial direction. May be.

According to the modification related to FIG. 5 and FIG. 6, the same operation and effect as in the above embodiment, except for the operation and effect related to the contact surfaces 42, 52 and 62 forming a V-shape in the above embodiment. Is played.
Further, according to the modification related to FIG. 6, the rotating component group R including the main rotating component 41 and the first and second auxiliary rotating components 51 and 61 is smaller in the radial direction than the embodiment. Can be

Referring to FIG. 7, the first and first sub-rotating parts 51 and 61 shown in FIG. 2 are in contact with the contact surfaces 52 and 62 of the main rotating part 41, respectively. Unlike the example in which the two secondary rotating parts 51 and 61 are arranged in parallel to the main rotating part 41, the first and second auxiliary rotating parts 51 and 61 are arranged in series with respect to the main rotating part 41. In this case, the contact surface 52 of the first sub-rotating component 51 contacts the contact surface 42 of the main rotating component 41, while the contact surface 62 of the second sub-rotating component 61 does not contact the contact surface 42, It contacts the contact surface 52 of the sub-rotation component 51.
According to this modification, the 1st, 2nd subrotation components 51 and 61 can be arrange | positioned compactly in the circumferential direction.

  As shown in FIG. 5 and FIG. 6, the rotation angle detection device 4 presses the contact surfaces 42, 52; 42, 62 together at the contact portions T 1, T 2 between the contact surfaces 42, 52; 42, 62. You may provide at least one of the main bullet member 45 (for example, spring) and the secondary bullet members 55 and 65 (for example, spring) which are urging members as a press member. In the case where the main bullet member 45 is provided, the main rotating component 41 rotates integrally with the output shaft 21 in the circumferential direction so as to be movable in the axial direction with respect to the output shaft 21 by, for example, serration coupling. Coupled so as to be immovable or almost immovable.

  According to this modified example, the rotation angle detection device 4 causes the contact surfaces 42, 52; 42, 62 to press each other at the contact portions T1, T2 between the contact surfaces 42, 52; , 55, 65, the contact surfaces 42, 52; 42, 62 are pressed against each other at the contact portions T1, T2 by the elastic members 45, 55, 65. The frictional force between 42 and 62 increases. As a result, the effect of preventing slippage between the contact surfaces 42, 52; 42, 62 is improved, and the detection accuracy of the rotation angles θ1, θ2 and the steering angle θ of the sub-rotating components 51, 61 is improved. .

In addition to the output shaft 21, the main rotating component 41 is a constituent member of the steering device 1, such as the input shaft 20 and the steering shaft 11, and is provided on a rotating member that rotates in a one-to-one correspondence with the steering wheel 10. Also good.
The magnetic detection element may be an element other than the magnetoresistive elements 71 and 72, for example, a Hall element or a coil. Further, the rotation angle sensor may be a sensor other than the magnetic detection element, for example, a light detection sensor for detecting light transmission / blocking.
The rotation angle sensor that detects the rotation angle of each of the sub-rotating components 51 and 61 may output the secondary detection signals S12 and S22 shown in FIG. 4 as detection signals.
Each contact surface 42, 52, 62 may be a cylindrical surface instead of the tapered surface F.
In the rotating component group R, the sub rotating component may be composed of one rotating component that rotates in conjunction with the main rotating component 41.
The outer diameter of the contact surface of the sub-rotation component may be larger than the outer diameter of the contact surface of the main rotation component.
In each of the contact surfaces 42, 52, 62, when the radial force at the contact portions T1, T2 (hereinafter referred to as “radial force”) is broken down into component forces perpendicular to the respective tapered surfaces F1, F2, By reducing the angle formed by the pair of tapered surfaces F1 and F2 so that the wedge effect in which the component force is greater than the radial force can be exhibited, the contact surfaces 42, 52; The frictional force acting on becomes larger. As a result, the effect of preventing slippage between the contact surfaces 42, 52; 42, 62 is improved, and the detection accuracy of the first and second rotation angles θ1, θ2 and the steering angle θ is improved.
The auxiliary force generator 6 may be a hydraulic type in addition to the electric type. Further, the steering device 1 may not include the auxiliary force generation device 6.
The main rotating component may be a driven rotating component that is rotationally driven by one sub rotating component as a driving rotating component. In this case, the rotating member provided with the main rotating component becomes the driven rotating member.
The machine provided with the rotation angle detection device 4 may be other than the steering device 1.

DESCRIPTION OF SYMBOLS 1 Steering device 4 Rotation angle detection device 5 Torque detection device 10 Steering wheel (steering operation member)
13 Housing (sensor housing)
21 Output shaft 41 Main rotating parts 42, 52, 62 Contact surface 49 Rotating angle detecting means 51, 61 Sub rotating parts 71, 72 Magnetoresistive element (rotating angle sensor)
81, 82 Magnet 45, 55, 65 Elastic member (pressing member)
θ Steering angle (rotation angle)
θ1, θ2 Rotation angle F, F1, F2 Taper surface T1, T2 Contact part

Claims (6)

A main rotating component that is provided on the rotating member and rotates integrally with the rotating member around a rotation center line; and a sub rotating component that rotates in conjunction with the main rotating component at a predetermined rotation ratio with respect to the main rotating component; A rotation angle detection device comprising: a rotation angle sensor that outputs a detection signal corresponding to the rotation angle of the sub-rotation component; and a rotation angle detection means that detects a rotation angle of the rotating member based on the detection signal.
A rotation angle detection device characterized in that the transmission of rotation between the main rotating component and the sub rotating component is performed by friction between contact surfaces of the main rotating component and the sub rotating component. The rotation angle detection device according to claim 1,
The sub-rotation component is a first sub-rotation component and a second sub-rotation component having the contact surface with an outer diameter different from the outer diameter of the contact surface of the first sub-rotation component,
The rotation angle of the sub rotation component is a first rotation angle of the first sub rotation component and a second rotation angle of the second sub rotation component,
The rotation angle sensor outputs a first detection signal that is the detection signal corresponding to the first rotation angle, and a second detection signal that is the detection signal corresponding to the second rotation angle. And a second rotation angle sensor for outputting a rotation angle sensor. In the rotation angle detection device according to claim 1 or 2,
The rotation angle detecting device, wherein the contact surface is a tapered surface. In the rotation angle detection device according to claim 3,
A vertical cross-sectional shape of each contact surface in a plane including the rotation center line is a V-shaped convex shape or a V-shaped concave shape formed by a pair of tapered surfaces. Detection device. The rotation angle detection device according to any one of claims 1 to 4,
The rotation angle detection apparatus comprising a pressing member that presses the contact surfaces to each other at a contact portion between the contact surfaces. A steering apparatus comprising: the rotation angle detection device according to any one of claims 1 to 5; a torque detection device that detects a steering torque by a steering operation member; and a sensor housing.
The rotation angle of the rotation member is a steering angle based on an operation of the steering operation member,
The rotation angle detection device is housed in the sensor housing together with the torque detection device.

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